|Salmonella enteritidis motility on MSRV
|Nonmotile Salmonella gallinarum on MSRV
MSRV (Modified Semisolid Rappaport - Vassiliadis) medium: this is an adaptation
of the original Rappaport - Vassiliadis medium for Salmonella isolation from feces
and foods, as described in SR EN ISO 6579 standard Annex D. The semisolid state
facilitates the motility of Salmonella. It is based on the ability of Salmonella species
to migrate in the selective medium by competing with the other motile organisms,
thus producing opaque halos of growth.
Tryptose 4.59 g, Casein enzymic hydrolysate 4.59 g, Sodium chloride 7.34 g,
Potassium dihydrogen phosphate 1.47 g, Magnesium chloride, anhydrous 10.93 g,
Malachite green oxalate 0.037 g, Agar 2.7 g, Distilled water ad 1000 ml.
Final pH ( at 25°C) 5.2±0.2
Prepared medium looks like greenish blue coloured clear to slightly opalescent
semisolid gel in Petri plates and may have a slight precipiate.
Escherichia coli ATCC 25922: poor growth / inhibited.
Salmonella Typhimurium ATCC 14028: abundant growth.
Soya peptone 5 g, Natriumchloride 8 g, Potassium dihydrogenphosphate 1.4 g,
Potassium monohydrogenphosphate 0.2 g, Magnesium chloride 40 g, Malachite
green solution 10 ml, Distilled water ad 1000 ml.
Adjust pH to 5.2 ± 0.2. Sterilize by autoclaving at 115 ºC for 15 minutes. The broth
should be clear and dark-blue.
Inoculate the medium with pre-enriched culture and incubate it for 24 hours at 42
°C. Addition of novobiocin (40 mg/litre) enhances the medium selectivity.
Preparation of malachite green solution: add 0.4 g malachite green in 100 ml
Medium used for selective enrichment of Salmonella with the exception of S. typhi and S. paratyphi A from foodstuffs, water and
pathologic materials accordingly to SR EN ISO 6579 standard "Horizontal method for the detection of Salmonella spp. ". It is used
after the pre-enrichment step.
(c) Costin Stoica
1. SR EN ISO 6579:2003/A1:2007. Microbiology of food and animal feeding stuffs -
Horizontal method for the detection of Salmonella spp. - Amendment 1: Annex D:
Detection of Salmonella spp. in animal faeces and in environmental samples from
the primary production stage (ISO 6579:2002/Amd 1:2007)
2. Himedia Laboratories. Semisolid Rappaport Vassiliadis Medium, Modified -
|Rappaport - Vassiliadis broth